Browse Prior Art Database

Programmable Self-Terminated Nets

IP.com Disclosure Number: IPCOM000114894D
Original Publication Date: 1995-Feb-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Daniels, L: AUTHOR [+4]

Abstract

Termination resistors for chip to chip interconnections of integrated circuit devices are conventionally designed into the construction of one or both of the chips. Disclosed here is the utilization of package conductor resistance to provide all or part of the termination resistance.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 65% of the total text.

Programmable Self-Terminated Nets

      Termination resistors for chip to chip interconnections of
integrated circuit devices are conventionally designed into the
construction of one or both of the chips.  Disclosed here is the
utilization of package conductor resistance to provide all or part of
the termination resistance.

      The required ohmic resistance is calculated based on the
topology of the nets under consideration by performing model
simulations.  The determined resistance of chip to chip
interconnection conductors can be set (programmed) to the calculated
value either through specification of its cross sectional area (i.e.,
width and thickness), its length, or both.  From practical
considerations, the length must, in general, be kept to a minimum to
reduce path propagation delay.  Commonly used conductor fabrication
techniques do not provide methods for varying thickness among
conductors.  Hence, resistance programming will, in most cases, be
most expeditiously accomplished through specification of conductor
width.  The change in characteristic impedance of the conductors
resulting from the change in cross section can be addressed through
selection of proper driver characteristics and series termination
resistance of the net.  In the case of non-critical nets for which
path delay is not a limitation, conductor length may be adjusted.
And, where the package fabrication technology provides the
capability, conductor thickness may also be specified...